A colony of ten dogs with subcutaneous closed tracheal pouches will be established in order to obtain sufficient amounts of normal respiratory mucus of initial chemical studies. These samples will be used to establish the nature and extent of mucus changes attributable to anesthesia and to the mechanical manipulations involved in the sampling. Tracheal mucus from healthy human donors will be obtained by direct aspiration under local anesthesia and under aspeptic conditions using a fiberoptic bronchoscope. Tracheal secretions from patients with such diseases as cystic fibrosis, emphysema, alveolar proteinosis, chronic bronchitis, and bronchiectasis will be obtained in a similar manner and utilized for the investigation of pathological mucins. For development studies, mucins will be obtained from organ culture of tracheobronchial explants taken from rates at various stages of development.